mass-scale electricity consumer 

One last time for everyone who slept through GTA 5’s story. Michael was never in witness protection. Dave and Steve were corrupt and misusing government resources for their own selfish ends. Dave independently used his department’s assets to protect a criminal (Michael) from justice. He helped him fake his death in order to hide him from both the government and his criminal enemies. He selfishly did this so he and Michael could craft an event (The Ludendorff Heist in Prologue) where Dave could pretend to heroically take down the criminal trio in order to advance his career. This worked, the FIB and everyone else were fooled and so Dave got promoted largely on the basis of him “killing” Michael. However, knowledge of this illicit deal was later used to blackmail him and Michael when Steve found out about it. Steve used the threat of telling the FIB about their deal, and the fact that Michael was still alive, to control them both during the game. If I stole a million dollars from the government and bought Pokémon cards, you wouldn’t call it ‘the government investing in Pokémon cards’. In the same way, Dave misusing government resources to trick the government into allowing a criminal to avoid jail, keep his stolen money, and live in a mansion isn’t ‘witness protection’. Calling it that is just a sarcastic, joking way to refer to the corruption. It IS a fake identity, similar to witness protection, but Michael was given it specifically to AVOID justice, not achieve it like actual witness protection deals. Rockstar themselves called this deal ‘informal witness protection’ in marketing prior to GTA V coming out, likely partly to be subtle and not spoil the story. If he were actually in witness protection, neither Rockstar nor Michael would jokingly need to refer to it as ‘informal’. They’d just say he was in witness protection.